The simplest way to calculate a percentage in Excel

To calculate a percentage in Excel, you divide the part by the whole, then multiply by 100. The fastest way is to type a formula into a cell: =A1/B1*100, where A1 is the part and B1 is the whole. Press Enter, and Excel shows the result.

If you have the numbers already in your spreadsheet, you do not need to type them again. Excel reads whatever is in those cells. For example, if cell A1 contains 25 and cell B1 contains 200, the formula =A1/B1*100 will return 12.5, which is the correct percentage.

You can also skip the multiplication by 100 and format the cell as a percentage instead. Type =A1/B1, press Enter, then right-click the cell and choose "Format Cells". Select "Percentage" from the Category list. Excel will automatically display the decimal as a percentage — so 0.125 becomes 12.5%.

Key Takeaways

  • The percentage formula is the part divided by the whole, multiplied by 100: =A1/B1*100.
  • You can also use =A1/B1 and then format the cell as a percentage, which Excel will display automatically.
  • To explore the same formula to many rows at once, enter it in one cell, then drag the small square at the bottom-right corner down to copy it.
  • If your result shows too many decimal places, right-click the cell, choose "Format Cells", and set the decimal places to the number you want.

Calculating percentage increase or decrease

A percentage increase or decrease compares an old value to a new value. The formula is: =(New - Old) / Old * 100. If the result is positive, the value went up. If it is negative, the value went down.

For example, if a price was $50 and is now $60, the formula would be =(60-50)/50*100, which equals 20%. The price increased by 20%. If the new price were $40, the result would be -20%, meaning a 20% decrease.

In a spreadsheet, if the old value is in B1 and the new value is in C1, type =(C1-B1)/B1*100. This works the same way whether you are tracking sales, inventory, test scores, or any other number that changes over time.

Copying a formula down to multiple rows

Once you have entered a formula in one cell, you can copy it to many cells below without retyping. Click the cell that contains your formula. You will see a small square in the bottom-right corner of the cell border — this is called the fill handle.

Click and drag that square downward to the last row where you want the formula to appear. As you drag, Excel highlights the cells you are selecting. When you release the mouse, Excel copies the formula to all those cells and automatically adjusts the cell references. If your formula was =A1/B1*100, the next row will automatically become =A2/B2*100, and so on.

This saves time when you have dozens or hundreds of rows. You enter the formula once, drag it down, and Excel does the math for every row in seconds.

Fixing decimal places and display format

Excel often shows percentages with many decimal places — for example, 12.5432% when you only want 12.5%. To control how many decimal places appear, right-click the cell or cells containing your percentages and select "Format Cells".

In the Format Cells window, click the "Numbers" tab if it is not already selected. Choose "Percentage" from the Category list on the left. You will see a field labeled "Decimal places" — type the number you want. If you type 1, Excel will show one decimal place. If you type 0, it will show whole numbers only.

Click OK, and Excel updates the display. The actual value in the cell does not change — only what you see on screen. This is useful when you are presenting data to someone else or printing a report.

Calculating what percentage one number is of another

This is the most common percentage task. You have two numbers and want to know what percent the first is of the second. The formula is always Part / Whole * 100.

Say you sold 45 items out of a goal of 200. What percentage of your goal did you reach? Type =45/200*100 and you get 22.5%. Or if those numbers are in cells, type =A1/B1*100. The order matters — the part always goes on top (in the numerator), and the whole always goes on the bottom (in the denominator).

A common mistake is reversing them. If you type =200/45*100, you get 444%, which is wrong. Remember: the smaller number (the part) goes first.

Using percentage formulas in real spreadsheets

Percentages appear in almost every type of spreadsheet. A sales tracker might show what percentage of monthly quota each person reached. A budget spreadsheet might show what percentage of the total budget each category uses. A grade sheet might show what percentage of points a student earned.

The formula stays the same in all cases: divide the part by the whole and multiply by 100. Once you have entered it correctly in one row, you can copy it down to every other row. If you need to change the format — to show fewer decimal places, or to display it as a percentage symbol instead of a number — right-click and format the cells.

The most important step is making sure your numbers are in the right cells before you write the formula. Take a moment to identify which number is the part and which is the whole, then build your formula around that.

Frequently Asked Questions

Why does my percentage formula show a decimal instead of a percentage?

If you used the formula =A1/B1 without multiplying by 100, Excel shows the result as a decimal (like 0.125). Either multiply by 100 in the formula to get 12.5, or right-click the cell, choose "Format Cells", select "Percentage", and click OK. Excel will display it as 12.5% automatically.

Can I calculate percentage of a total across multiple cells?

Yes. If you want to know what percentage one cell is of the sum of many cells, use =A1/SUM(A1:A10)*100. This divides the value in A1 by the total of cells A1 through A10. You can adjust the range to match your data.

What does the dollar sign mean in a formula like $B$1?

The dollar signs lock that cell reference so it does not change when you copy the formula down. If you want to divide many cells by the same total, use =A1/$B$1*100. When you drag this formula down, A1 becomes A2, A3, and so on, but B1 stays as B1. This is useful when you have one total at the bottom and want to calculate what percentage each row is of that total.

How do I show a percentage with a % symbol instead of a number?

Use the formula =A1/B1 without multiplying by 100, then right-click the cell and choose "Format Cells". Select "Percentage" from the Category list and click OK. Excel will display it as 12.5% instead of 12.5.